The proposed study seeks to identify the feasibility of adopting a newly developed technology platform (hardware and software) to detect and monitor the response of neoplasms of the breast to neoadjuvant chemotherapy based on analysis of dynamic measures of the vascular response and hemoglobin states. This technology employs nonionizing optical sources and performs rapid volumetric, multi-wavelength optical measures from which are derived signatures of vascular reactivity and indicators of tissue oxygen supply/demand. Methodological feasibility will be assessed by evaluating three specific aims. 1) We will introduce software updates to serve to further automate system capability thereby facilitating the collection and analysis of key system quality control parameters. This will allow determination of system performance and online feedback of its readiness. 2) We will introduce additional illumination/detection sites into the adjustable measuring head and optimize their location. Guiding these studies will be simulation of 3D hemispheric models of the breast containing various inclusions and similar studies using laboratory phantoms. 3) For a limited number of healthy volunteers and subjects diagnosed with breast cancer, we will quantify and characterize the dynamic response of the breast to various homeostatic provocations. In latter case, these studies will be repeated at various times during the course of neoadjuvant therapy. The collected surface detector data and reconstructed 3D image time series will be analyzed using various time series analysis and statistical methods to reveal significant differences among the test groups to the induced homeostatic provocations.